Roof load transfer system

ABSTRACT

A system provides a continuous load path from a top wall plate of a building to a foundation of the building. A wire rope is disposed between the top plate of the building and the foundation of the building. A first attachment is coupled to the foundation to connect a lower end of the wire rope to the foundation. A second attachment is coupled to the top plate to connect an upper end of the wire rope to the top plate of the building.

FIELD

Wood frame buildings and constructing buildings that resist wind loads.

BACKGROUND

Subsequent to Hurricane Andrew in 1992, there has been an increased interest in constructing buildings to be more resistant to wind damage. In particular, §2.1.2 of the American Forest and Paper Association Wood Frame Construction Manual 1995 SBC High Wind Edition requires a continuous load path from the roof to the foundation to resist uplift and overturning loads.

At present the accepted means of providing a continuous load path from the roof to the foundation is through the use of galvanized steel construction connectors such as those manufactured by SIMPSON STRONG-TIE® or KANT-SAG®. A typical application may include rafter ties at the top plate, strap ties at the second floor band-joist and more ties at the foundation, with corner hold-downs.

All these connectors are attached to the wood framing; the framing providing the load path between the various connectors. Each connector is fastened to the framing members with nails or screws. A 20 by 30 foot two-story residence might easily require some 200 plus individual connectors. Typical practice is to fasten each rafter to the stud below, and to strap the studs across the rim joists at each floor, and at the foundation. Each strap or tie may require anywhere from 8 to 24 or more nails. The entire system relies on many individual nailed connections. It is completely impractical to retrofit existing construction unless the structure is completely gutted for renovation and even then compromises may have to be made.

U.S. Pat. No. 6,843,027 attempts to simplify the process by a system of cables and tensioners that secure each rafter and the top plate to the foundation at multiple points with a continuous cable that loops over each rafter and back down into the wall. It is necessary to drill many holes and pull the cable through the holes to essentially “sew” the house together.

It is believed that a need remains for a less laborious method for providing a continuous load path from the roof to the foundation of a wood frame house or other building.

SUMMARY

In one embodiment, a method provides a continuous load path from a top plate of a wall of a building to a foundation of the building. The method includes attaching a lower end of a wire rope to the foundation of the building, removing slack from the wire rope, and attaching an upper end of the wire rope to the top plate of the wall of the building.

In another embodiment, a kit provides a continuous load path from a top plate of a wall of a building to a foundation of the building. The kit includes a wire rope having a length sufficient to connect the foundation of the building to the top plate of the building, first attachment hardware attached to a first end of the wire rope for attaching the wire rope to the foundation, at least one fastener to attach the first attachment hardware to the foundation, a compression plate dimensioned to lie on top of the top plate, and second attachment hardware to attach the wire rope to the compression plate.

In yet another embodiment, a system provides a continuous load path from a top wall plate of a building to a foundation of the building. The system includes a wire rope disposed between the top plate of the building and the foundation of the building. It also includes a first attachment coupled to the foundation to connect a lower end of the wire rope to the foundation, and a second attachment coupled to the top plate to connect an upper end of the wire rope to the top plate of the building.

In a further embodiment, a wall or a wall portion for a building includes an upper structural member, a first covering and a second covering, the first covering and the second covering defining an interior of the wall or wall portion. The wall or wall portion also includes a wire rope disposed within the interior of the wall or wall portion, an upper end of the wire rope attached to or attachable to the upper structural member, a lower end of the wire rope attached to or attachable to a foundation of the building so that the wire rope provides a continuous load path from the upper structural member to the foundation.

In yet an additional embodiment, a building provides a continuous load path from a top wall plate of the building to a foundation of the building. The building includes a wire rope disposed between the top wall plate of the building and the foundation of the building. A first attachment is coupled to the foundation to connect a lower end of the wire rope to the foundation; and a second attachment is coupled to the top plate to connect an upper end of the wire rope to the top plate of the building.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a portion of one embodiment of a wall that has a wire rope to provide a direct load path from the top plate to the foundation;

FIG. 2 illustrates a perspective sketch of a building having wire ropes to provide direct load paths from the top plates to the foundation;

FIG. 3 illustrates one embodiment of a connection between a foundation and a wire rope, the connection employing an anchor bolt;

FIG. 3A illustrates, in perspective, the embodiment shown in FIG. 3.

FIG. 4 illustrates one embodiment of a connection between a foundation and a wire rope, the connection employing a plate attached to the foundation.

FIG. 4A illustrates, in perspective, the embodiment shown in FIG. 4.

FIG. 5 illustrates one embodiment of a connection between a top plate of a wall and a wire rope;

FIG. 6 illustrates one embodiment of a connection between a foundation and a wire rope in a building wherein a floor rests on the foundation;

FIG. 7 is a flow diagram illustrating one embodiment of a method for providing a direct load path from a top plate of a building to the foundation; and

FIG. 8 illustrates one embodiment of a kit.

DETAILED DESCRIPTION

The embodiments discussed herein provide methods and apparatus for providing a load path between a roof or a top plate of a building and a foundation of the building. The load path is for resisting wind or earthquake loads. It is particularly directed toward wood frame buildings. Advantage is taken of the fact that a wall of a wood frame building, generally, has excellent strength for resisting vertical bending loads. This is particularly true for buildings that employ walls covered with plywood sheathing, or buildings that employ walls covered with sheathing that runs diagonally between a sill plate and a top plate of the wall. This is generally true even for walls having windows or doors.

An embodiment may comprise a single wire rope for each wall, to carry lifting or overturning loads from the top plate to the foundation of the building. FIG. 1 illustrates, in one embodiment, a wall or wall portion 100 enclosing a wire rope 104 for carrying a direct load from the top plate 110 to the foundation 106, bypassing the sill plate 108. The arrangement includes an attachment 130 between the wire rope 104 and the foundation 106. It also includes an attachment 132 between the top plate 110 and the wire rope 104. The wire rope 104 may be installed between a first wall covering 120 and a second wall covering 122. Electrical cables and insulation (not shown) also may be placed between the first wall covering 120 and the second wall covering 122 without interfering with the wire rope 104. The top plate 110 may comprise two two-by-fours laminated together, and the sill plate 108 may likewise comprise two two-by-fours. Laminated two-by sixes may also be employed for the plates 108 and 110. Finished two-by-fours have thickness and width of about 1⅝″×3⅝″ (4.127 cm×9.2 cm). Finished two-by sixes have a width of about 5⅝″ (14.3 cm)

The wire rope 104 may, for example, be characterized by a diameter of about ⅜″ (0.9525 cm) to ½″ (1.27 cm) or greater diameter. It may be sized to accommodate the maximum load expected due to lifting or overturning forces due to wind, or due to seismic loads.

The first wall covering 122 may comprise drywall, and it may have a thickness of about ½″ (1.27 cm). The second wall covering 122 may, for example only, comprise ⅝″ (1.58 cm) plywood, or ⅝ (1.58 cm) sheathing boards positioned diagonally. Studs comprising two-by-fours or two-by sixes may be located between the first wall covering 120 and the second wall covering 122. Aluminum or steel studs may alternatively be employed. The invention may be applied to concrete block or other wall types provided the wall has the needed internal space, and sufficient strength to withstand the vertical bending loads.

FIG. 2 illustrates a perspective sketch of a building having wire ropes to provide direct load paths from the top plates to the foundation. In one embodiment, a building 200 comprises a foundation 106, a front wall 202 including top plate 110, an end wall 204 including top plate 216 and a gable end 206. The building 200 also comprises a roof 208, a door 214 and a pair of windows 210 and 212. The wire rope 104 is installed inside the front wall 202 to provide a load path between the top plate 110 and the foundation 106. Although not shown, one skilled in the art will appreciate that rafter ties may be employed to connect the roof 208 to the top plate 110.

Likewise, a wire rope 104 may be installed inside the end wall 204 to provide a load path between the top plate 216 and the foundation 106. One skilled in the art will appreciate that conventional framing connections may be employed to connect the gable end 206 to the top plate 216, and the gable end 206 to the roof 208.

FIG. 3 illustrates one embodiment of a connection between a foundation and a wire rope, the connection employing an anchor bolt. In one embodiment, the first attachment 130 connects the wire rope 104 to the foundation 106. The attachment 130 may include an anchor bolt 300 embedded into the foundation 106. The wire rope 104 may include a socket 302 (e.g., a spelter socket) installed at the factory to the lower end 304 of the wire rope 104. The anchor bolt 300 may be attached to an eye fitting 306 that is secured by a jam nut 308. The eye fitting 306 may be engaged to the socket 302 by a clevis pin or a bolt 310, to attach the wire rope 104 to the foundation 106. If the foundation 106 is comprised of concrete, the anchor bolt 300 may be installed when the foundation 106 is cast. The anchor bolt 300 may pass through a hole (not shown) in sill plate 108.

FIG. 3A illustrates, in perspective, the embodiment shown in FIG. 3. The sill plate 108 is not shown in this figure.

FIG. 4 illustrates one embodiment of a connection between a foundation and a wire rope, the connection employing a plate attached to the foundation. The illustrated embodiment shows an alternative configuration of the first attachment 130 to connect the wire rope 104 to the foundation 106. Connection may be facilitated by plate 400 attached to the foundation 106 by the expansion bolts 405. The plate 400 may include an eye fitting 402. In one embodiment, the wire rope 104 may comprise a factory-installed socket 302 that may be attached to the eye fitting 402 by the clevis pin or the bolt 310. A person skilled in the art will note that the assembly of the socket 302 to the eye fitting 402 provides a connection that utilizes the full strength of the wire rope 104, because the socket 302 comprises a pair of side portions 303 that are configured to engage the clevis pin or the bolt 310; the side portions 303 being symmetrically disposed on each side of eye fitting 402, thus transferring load to the wire rope 104 without bending the wire rope 104

FIG. 4A illustrates, in perspective, the embodiment shown in FIG. 4. The sill plate 108 is not shown in this figure. The embodiment illustrated in FIGS. 4 and 4A is particularly intended for retrofitting existing buildings. The wire rope 104 should be directed into the internal space between the first wall covering 120 and the second wall covering 122. This should be done in a manner that results in the wire rope 104 being as straight as possible in its final configuration, since it must carry tension. A person skilled in the art would be prepared to do this.

FIG. 5 illustrates one embodiment of a connection between a top plate of a wall and a wire rope. The illustrated embodiment shows a configuration that may be employed for the second attachment 132, to attach the wire rope 104, having upper end 510, to the top plate 110. A compression plate 502 may overlay the top plate 110, and a hole (not shown) in the compression plate 502 may be aligned with a hole (not shown) in the top plate 110, so that the wire rope 104 may be passed therethrough. Attachment may be facilitated by a socket 504 and a wedge 506, and may be secured by swageable ring 508. The wedge 506 may be conical and it may have a radial cut on one side, so when it is pounded into socket 504, it collapses onto wire rope 104. Socket 504 may have an inside taper that substantially matches an outside taper on wedge 506. Compression plate 502 may apply force over a large area on the top plate 110 to prevent damage to top plate 110. A person skilled in the art will be prepared to remove slack from the wire rope 104.

FIG. 6 illustrates a first attachment 130 for a building in which a floor 600 comprising joists 610, sub-floor 620 and flooring 630 is placed on foundation 106. The illustrated embodiment shows the first attachment 130 that may comprise the plate 400 attached to the foundation 106 by the expansion bolts 405. The plate 400 may include the eye fitting 402, and the wire rope 104 may include the factory-installed socket 302. The socket 302 may be engaged to the eye fitting 402 by the clevis pin or the bolt 310. A person skilled in the art will note that the assembly of the socket 302 to the eye fitting 402 provides a connection that utilizes the full strength of the wire rope 104, because the socket 302 comprises a pair of side portions 303 that are configured to engage the clevis pin or the bolt 310; the side portions 303 being symmetrically disposed on each side of eye fitting 402, thus transferring load to the wire rope 104 without bending the wire rope 104.

FIG. 7 is a flow diagram illustrating one embodiment of a method for providing a direct load path from a top plate of a building to the foundation. The illustrated embodiment shows a method for providing a load path from the top plate 110 of the building 200 to the foundation 106. After starting 700, the first end 304 of wire rope 104 is attached 710 to the foundation 106. The wire rope 104 is placed 720 in a space to be enclosed between the first wall covering 120 and the second wall covering 122 of the building 200. A first hole is formed 730 through the top plate 110 and the compression plate 502 is placed 740 upon the top plate 110. The wire rope 104 is passed 750 through the first hole in the top plate 110 and a second hole in the compression plate 502. Slack is removed 760 from the wire rope 104. The wire rope 104 is attached 770 to the top plate 110 by the socket 504 and the wedge 506. A swageable ring 508 is applied 780 to secure wedge 506. The rafter ties are applied 790 to provide a load path from the roof 208 to the top plate 110.

FIG. 8 illustrates one embodiment of a kit 800. Kit 800 may comprise a wire rope 810 characterized by a length sufficient to connect the foundation of a building to a top plate of the building. The wire rope 810 may include a first attachment hardware 820 attached to one end thereof. The first attachment hardware 820 may be, for example, the socket 302. One or more fasteners 830, which may include the anchor bolt 300 or the plate 400 and expansion bolts 405, also may be included in kit 800. A compression plate 840 may be provided, as well as second attachment hardware 850. A plurality of rafter ties 860 may also be provided.

While various embodiments have been described in the preceding discussion, it should be understood that many other embodiments fall within the scope of the attached claims. 

1. A method for providing a continuous load path from a top plate of a wall of a building to a foundation of said building, said method comprising: attaching a first end of a wire rope to said foundation; removing slack from said wire rope; and attaching a second end of said wire rope to said top plate of said wall of said building.
 2. The method according to claim 1 comprising placing said wire rope between first and second coverings forming said wall.
 3. The method according to claim 2 comprising forming a hole through said top plate of said wall and passing said second end of said wire rope through said hole.
 4. The method according to claim 1 comprising: forming a first hole through said top plate; placing a compression plate on said top plate, said compression plate defining a second hole; passing said wire rope through said first hole and through said second hole of said compression plate on said top plate; and attaching said wire rope to said compression plate by way of at least one wedge.
 5. The method according to claim 1 comprising installing a substantially vertical anchor bolt into said foundation and attaching said first end of said wire rope to said substantially vertical anchor bolt.
 6. The method according to claim 1 comprising attaching a plate to said foundation and attaching said first end of said wire rope to said plate.
 7. The method according to claim 1 wherein said wire rope comprises a socket at a first end of said wire rope, and said method comprises attaching said socket to said foundation.
 8. The method according to claim 1 comprising attaching at least one portion of a rafter tie to said top plate and attaching a second portion of said rafter tie to a roof of said building.
 9. A kit for providing a continuous load path from a top plate of a wall of a building to a foundation of said building, said kit comprising: a wire rope having a length sufficient to connect said foundation of said building to said top plate of said building; first attachment hardware attached to a first end of said wire rope for attaching said wire rope to said foundation; at least one fastener to attach said first attachment hardware to said foundation; a compression plate dimensioned to lie on top of said top plate; and second attachment hardware to attach said wire rope to said compression plate.
 10. The kit according to claim 9 wherein said first attachment hardware comprises a socket.
 11. The kit according to claim 9 wherein said second attachment hardware comprises a socket and wedge assembly to attach to said wire rope.
 12. The kit according to claim 11 further comprising a swageable ring to secure said wedge.
 13. The kit according to claim 9 further comprising a plurality of rafter ties to provide a continuous load path from a roof of said building to said top plate.
 14. A system to provide a continuous load path from a top wall plate of a building to a foundation of said building, said system comprising: a wire rope disposed between said top plate of said building and said foundation of said building; a first attachment coupled to said foundation to connect a first end of said wire rope to said foundation; and a second attachment coupled to said top plate to connect a second end of said wire rope to said top plate of said building.
 15. The system according to claim 14 wherein said first attachment comprises a substantially vertical anchor bolt attached to said foundation.
 16. The system according to claim 14 wherein said first attachment comprises a plate disposed on a substantially vertical surface of said foundation, said plate to attach to said foundation by at least one expansion bolt.
 17. The system according to claim 14 wherein said first attachment comprises a socket.
 18. The system according to claim 14 wherein said second attachment comprises a compression plate disposed on said top plate of said building.
 19. The system according to claim 18 wherein said second attachment further comprises at least one wedge to attach said wire rope to said compression plate.
 20. The system according to claim 14 further comprising at least one rafter tie to connect at least one rafter of said building to said top plate.
 21. A wall or wall portion for a building, said wall or wall portion comprising: an upper structural member; a first covering; a second covering, said first covering and said second covering defining an interior of said wall or wall portion; and a wire rope disposed within said interior of said wall or wall portion, a second end of said wire rope attached to or attachable to said upper structural member, a first end of said wire rope attached to or attachable to a foundation of said building so that said wire rope provides a continuous load path from said upper structural member to said foundation.
 22. The wall or wall portion according to claim 21 wherein said wall or wall portion is attachable to said foundation of said building.
 23. The wall or wall portion according to claim 21 wherein said wall or wall portion is attachable to a floor of said building.
 24. The wall or wall portion according to claim 21 comprising a socket attached to said first end of said wire rope.
 25. The wall or wall portion according to claim 21 comprising a socket and wedge assembly for attaching said second end of said wire rope to said upper structural member.
 26. A building to provide a continuous load path from a top wall plate of said building to a foundation of said building, said building comprising: a wire rope disposed between said top wall plate of said building and said foundation of said building; a first attachment coupled to said foundation to connect a first end of said wire rope to said foundation; and a second attachment coupled to said top plate to connect a second end of said wire rope to said top plate of said building.
 27. The building according to claim 26 wherein said first attachment comprises a substantially vertical anchor bolt attached to said foundation.
 28. The building according to claim 26 wherein said first attachment comprises a plate disposed on a substantially vertical surface of said foundation, said plate attached to said foundation by at least one expansion bolt.
 29. The building according to claim 26 wherein said first attachment comprises a socket.
 30. The building according to claim 26 wherein said second attachment comprises a compression plate disposed on said top wall plate of said building.
 31. The building according to claim 30 wherein said second attachment further comprises at least one wedge to attach said wire rope to said compression plate.
 32. The building according to claim 26 further comprising at least one rafter tie to connect at least one rafter of said building to said top plate. 